PDCD1 and melanoma: In October 2015, the FDA granted accelerated approval to the first combination immune checkpoint inhibitor, the programmed cell death protein 1 (PD1) inhibitor nivolumab and the cytotoxic T lymphocyte antigen 4 (CTLA4) inhibitor ipilimumab, for BRAFV600 unresectable or metastatic wildtype melanoma [7].